<template>
  <div class="goods-image">
    <div class="large" v-show="show" :style="[{ backgroundImage: `url(${images[currIndex]})`},l_position] "></div>
    <div class="middle" ref="target">
      <img :src="images[currIndex]" alt="">
      <div class="layer" v-show="show" :style="m_position"></div>
    </div>
    <ul class="small">
      <li v-for="(img, i) in images" :key="img" :class="{ active: i === currIndex }">
        <img @mouseenter="currIndex=i" :src="img" alt="">
      </li>
    </ul>
  </div>
</template>
<script>
import { reactive, ref, watch } from 'vue'
import { useMouseInElement } from '@vueuse/core'
export default {
  name: 'GoodsImage',
  props: {
    images: {
      type: Array,
      default: () => []
    }
  },
  setup(props) {
    const currIndex = ref(0)

    //放大镜
    const target = ref(null)
    const show = ref(null)
    const { elementX, elementY, isOutside } = useMouseInElement(target)
    //遮罩层坐标 
    const m_position = reactive({
      left:0,
      top:0
    })
    //大图坐标
    const l_position = reactive({
      backgroundPositionX:0,
      backgroundPositionY:0
    })
    watch([elementX, elementY, isOutside], () => {
      // console.log(elementX.value,elementY.value,isOutside.value)
      if(elementX.value < 100) {
        m_position.left = 0
      }else if(elementX.value> 300) {
        m_position.left = 200
      }else {
        m_position.left = elementX.value - 100
      }

      if(elementY.value < 100) {
        m_position.top = 0
      }else if(elementY.value> 300) {
        m_position.top = 200
      }else {
        m_position.top = elementY.value -100
      }

      l_position.backgroundPositionX = -2 * m_position.left +'px'
      l_position.backgroundPositionY = -2 * m_position.top +'px'

      m_position.left = m_position.left + 'px'
      m_position.top = m_position.top +'px'
      show.value = !isOutside.value
    })
    return { currIndex, target,l_position,m_position,show}
  }
}
</script>
<style scoped lang="less">
.goods-image {
  width: 480px;
  height: 400px;
  position: relative;
  display: flex;
  z-index: 500;

  .large {
    position: absolute;
    top: 0;
    left: 412px;
    width: 400px;
    height: 400px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    background-repeat: no-repeat;
    background-size: 800px 800px;
    background-color: #f8f8f8;
  }

  .middle {
    width: 400px;
    height: 400px;
    background: #f5f5f5;
    position: relative;
    cursor: move;

    .layer {
      width: 200px;
      height: 200px;
      background: rgba(0, 0, 0, .2);
      left: 0;
      top: 0;
      position: absolute;
    }
  }

  .small {
    width: 80px;

    li {
      width: 68px;
      height: 68px;
      margin-left: 12px;
      margin-bottom: 15px;
      cursor: pointer;

      &:hover,
      &.active {
        border: 2px solid @xtxColor;
      }
    }
  }
}
</style>